How to process output of a i2c sensor to get proper values.

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•

maze1980

Just a code snipped:

var addr = 0x76; //chip addr
read = function(reg, len) {
  i2c.writeTo(addr, reg);
  return i2c.readFrom(addr, len);
};
write = function(reg, data) {
  i2c.writeTo(addr, [reg, data]);
};

var register = 0x12
var length = 8
var data = new Uint8Array(length);
data.set(read(register, length));
var a1 =  (data[0] << 12) | (data[1] << 4) | (data[2] >> 4);

I didn't try/check your code in detail, but I'd suggest to define data (or b) as Uint8Array.

•

AkosLukacs in reply to @maze1980
Looks like I2C.readFrom already returns an Uint8Array, so I think you are doing a double allocation.
Not sure, but I think your memory usage might be smaller with just:
```
var data = read(register, length);
```
Or not, or might not even be measurable, if that allocation is just in a small function, and the GC frees up memory...

•

maze1980 in reply to @AkosLukacs
```
is the same size as 
```
var data; data.set(read(register, length));```

This function is used quite often in the examples:
https://www.espruino.com/Reference#l_ArrayBufferView_set

How to process output of a i2c sensor to get proper values.

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